Microbubble generator for the transfer of oxygen to microbial inocula, and microbubble generator immobilized cell reactor

Abstract

A microbubble generator is disclosed for optimizing the rate and amount of oxygen transfer to microbial inocula or biocatalysts in bioreactor systems. The microbubble generator, and an associated immobilized cell reactor, are useful in the detoxification and cleanup of non-volatile polymeric and volatile organic-contaminated aqueous streams. In particular, they are useful in the continuous mineralization and biodegradation of toxic organic compounds, including volatile organic compounds, associated with industrial and municipal effluents, emissions, and ground water and other aqueous discharges. One embodiment of the invention includes a microbubble chamber packed with small inert particles through which a liquid effluent and oxygen or another gas are admitted under pressure, followed by a venturi chamber to further reduce the size of bubbles.

Having described the invention, what is claimed is: 
     
       1. An apparatus for facilitating high oxygen levels in a liquid, comprising: (a) a first chamber packed with inert solid particles of small diameter, said first chamber having at least one inlet through which an oxygen-containing gas and a liquid can be admitted under pressure into said first chamber and contacted together to form mixed liquid-gas phases in which the gas is dispersed as bubbles, and an outlet through which the mixed liquid-gas phases can be removed from said first chamber; and   (b) a second chamber of venturi configuration, said second chamber having an inlet connected to the outlet of said first chamber through which the mixed liquid-gas phases from said first chamber can be admitted, and forced therethrough under pressure to further reduce the size of the bubbles of the mixed liquid-gas phases, and an outlet for the discharge of the mixed liquid-gas phases.   
     
     
       2. The apparatus of claim 1 wherein said second chamber is contained within an enclosing wall which forms at least part of said first chamber. 
     
     
       3. The apparatus of claim 2 wherein an enclosing wall forms said first chamber, said enclosing wall having a cover which, on removal, provides a means for the addition or removal from said first chamber of the inert solid particles. 
     
     
       4. The apparatus of claim 1 wherein the apparatus is of elongate shape having first and second ends, wherein each inlet of said first chamber is located near the first end, and wherein the second chamber is of a venturi configuration, the inlet of which is located near the second end and the outlet of which is located near the first end. 
     
     
       5. The apparatus of claim 4 wherein a drain outlet is located near the outlet from said second chamber. 
     
     
       6. An apparatus for facilitating high oxygen levels in a liquid, comprising a compartmented vessel, said compartmented vessel having first and second compartments, wherein: (a) said first compartment comprises enclosing side, top, and bottom walls, wherein said first compartment is packed with inert solid particles of small diameter, and wherein said first compartment has at least one inlet through which an oxygen-containing gas and a liquid can be admitted under pressure into said first compartment and contacted together to form mixed liquid-gas phases in which the gas is dispersed as bubbles, and an outlet through which the mixed liquid-gas phases can be discharged from said first compartment; and   (b) a second compartment of venturi configuration, wherein said second compartment is vertically supported within and surrounded by said enclosing walls, and has an inlet through which the mixed liquid-gas phases formed within said first compartment can be introduced under pressure, and forced therethrough to further reduce the size of the bubbles of the mixed liquid-gas phases, and an outlet for the discharge of the mixed liquid-gas phases.   
     
     
       7. The apparatus of claim 6 wherein the apparatus is of elongate shape having first and second ends, wherein each inlet of said first compartment is located near the first end, the inlet of said second compartment is located near the second end, and the outlet of said second compartment is located near the first end. 
     
     
       8. The apparatus of claim 7 wherein a drain outlet is located in the wall enclosing said first compartment near the inlet to said second compartment. 
     
     
       9. The apparatus of claim 6 wherein at least one of said enclosing walls has a cover which, on removal, provides a means for the addition or removal from said first compartment of the inert solid particles.